Drobo does not recognize/accept new Samsung Spinpoint F4 2TB?

My Drobo FS does not recognize my new Samsung Spinpoint F4 2TB, only for seconds. I insert the drive, the LED of the bay goes green and then off after some seconds.

I tried it now with two brand new drives. What´s wrong there?

I have already two 2TB Western Digital WD10EARS in the drobo. Other WDs does the Drobo also accept, only the Samsung Spinpoint F4 he does not??

Please open a support ticket.